English:
The „Kaiserstuhl“ (literally: the Emperor's chair) is a relatively low mountain range – a Mittelgebirge – with a miaximal height of 556.60m above sea level of volcanic origin located in the South West of Baden-Würtemberg. In terms of natural regions it is considered part of the Upper Rhine Plain. It reaches up to 377,10m above the level of the Rhine downstreams from the weir close to Burkheim.

At its utmost spread from the Michaelsberg close to Riegel in the northeast to the Fohrenberg close to Ihringen in the southwest, the Kaiserstuhl is about 15km long. Its maximum width is about 12.5km. His highest mountain is the Totenkopf (death's head) with 556,60m.

Geology
The formation of the Kaiserstuhl volcano during the Tertiary was the climax and at the same time the end of volcanic activity in the Upper Rhine Valley Rift. Volcanic activity, of which we still see numerous, today heavily eroded volcanic vents, started as early as the Cretaceous. The Kaiserstuhl is the only larger volcano from this period in the rift valley. Geologically the Kaiserstuhl can be divided into two parts: the sedimentary and volcanic part. Due to these peculiarities the Kaiserstuhl has been labeled one of the most important national geotopes.
The horizontal sedimentary layers forming the Eastern third of the Kaiserstuhl date back to the Jurassic and the Tertiary long before the volcanic activity. Important stratigraphic outcrops are the Hauptrogenstein (local Oolite) which is found mainly near the village of Riegel and the Pechelbronner Schichten (local tertiary layers in the South-German Scarplands) near Bötzingen. During the formation of the Upper Rhine Plain this part of the Kaiserstuhl sloped less in respect to its surrounding area – and thus appears as a so-called horst. (wiki-link) As to its geological structure and the sequence of the escarpments the Kaiserstuhl is comparable to the nearby Tuniberg, Nimberg and also to the Schönberg, which is situated South of the City of Freiburg.
Petrologically the volcanic Kaisersuhl is an alkali-carbonate rock formation. The volcanic rocks making up a large part of the central and Western Kaiserstuhl were the result of numerous volcanic eruptions during the Miocene, about 19 to 16 million years ago. They cover parts of the sedimentary base of the Eastern Kaiserstuhl, which is why in some places changes in the base’s mineralogical composition occurred. The driving force behind this process of contact metamorphism was an increase in temperature. Due to the alternate eruption of Tephra and lava flows from several vents a complex stratovolcano came into existence. Some of the rising magma solidified as volcanic intrusions bellow the surface - and today forms the central part of the Kaiserstuhl. Laterally rising phonolite magma also intruded into the sedimentary base of the Eastern Kaiserstuhl. Up to today several hundred meters of the original volcano have been eroded.
The entire volcanic Kaiserstuhl consists of stones that contain elements of foids and olivine and are not saturated with SiO2. Most igneous rocks on the surface are leucite-tephrites, subordinately also phonolites, limburgites, and olivine-nephelinites (at the Limbert Mountain near Sasbach). The latter of which is rich in xenotliths from the earth’s mantle. Regarding the igneous rocks carbonatite ignimtbrite and lapilli have to be mentioned as peculiarities. They can be found in places in the Western part of the Kaiserstuhl (Henkenberg near Burkheim, Kirchberg near Oberrotweil).
The subvolcanic rocks and lode rocks of the central Kaiserstuhl, on the contrary, are plutonic equivalents of the erupted material (essexite, carbonatite and coarse granular phonolite). For different varieties of the ode rocks several terms can be found, some of which have not been acknowledged. Of big scientific interest is the consolidated carbonatite neat Altvogtsburg und Schelingen. It is a quite rare volcanic rock, which through crystallization originated from a carbonite magamatic melt, not a silicate one. Due to this extraordinary situation the magmatic nature of the carbonatite has not been realized for a long time or put into doubt. Alternative interpretations suggested it was a metamorphologically altered sedimentary (rock which had undergone metamorphosis); examples of which can be found nearby. Only in the 1950s and 1960s researches succeeded in giving proof of it being a carbonite; one of the clues were the eruptive carbonatites found in the Western part of the Kaiserstuhl. Containing the Niob-mineral Koppit, experiments to retrieve the carbonatite rock by mining were carried out in the middle of the 20th century. However, the amount turned out to be too small for using them more intensely.
The Kaiserstuhl is toady largely covered by a quaternary loess layer.

Logging Requirements

Answer the following questions:

A. What classification is the grain size of the igneous rocks, that can be found in open places in the Western part of the Kaiserstuhl?

B.) Up to what size in millimeters according to the IUGS (International Union of Geological Science) divided?

C.) Write in you email the number of steps of the large stone object nearby.

Only if your answers are uncorrect you will get an response! Don’t write your answers into your log, otherwise your log will be deleted.
Please add a picture of your GPSr and/or yourself at the final area into you internet-log